DB2 Server for VSE & VM: Application Programming

Condition Handling with LE/VSE (DB2 Server for VSE)

The DB2 Server for VSE environment is sensitive to errors or conditions. A failing SQL transaction or application can potentially leave a DB2 Server for VSE database in an inconsistent state. For this reason, it is essential that DB2 Server for VSE knows about the failure of a transaction or application that has been updating a database so that it can perform database rollback.

When a user runs an application with the TRAP(ON) run-time option of LE/VSE and the DB2 Server for VSE application is running in Single User Mode, LE/VSE and DB2 Server for VSE keep track of calls to and returns from the database. If a program interrupt or abend occurs when the application is running, the LE/VSE condition manager is informed whether the problem occurred in the application or in the database manager. If the program interrupt or abend occurs in the database manager, the LE/VSE condition handler passes the condition back to DB2 Server for VSE.

If a program interrupt or abend occurs in the application outside the database manager, the LE/VSE condition manager will perform its own condition handling actions. If the condition manager gets control then the user must do one of the following:

• Resolve the error completely so that the application can continue.
• Make sure that the application terminates abnormally by using the ABTERMENC(ABEND) run-time option of LE/VSE to transform all abnormal terminations into operating system abends in order to cause DB2 Server for VSE to do the necessary recovery processing when the DB2 Server for VSE server is warm started.

  Note:

  The following methods are available for specifying any LE/VSE run-time options, including ABTERMENC(ABEND): As an installation wide default through the CEEDOPT assembler language source file. In the assembler user exit routine CEEBXITA. As an application default through the CEEUOPT assembler language source file. CEEUOPT is assembled into an object module which is linked with the application program. In JCL through the PARM parameter of the JCL EXEC statement. In PL/I source code through the PLIXOPT string.

  See the IBM Language Environment for VSE/ESA Programming Guide for more details.

• Provide a modified run-time assembler user exit (CEEBXITA) that transforms all abnormal terminations into operating system abends. The assembler user exit should check the return code and reason code or the CEEAUE_ABTERM bit, and request an abend by setting the CEEAUE_ABND flag to ON, if appropriate.

  Note:

  CEEBXITA assembler user exit is intended for use by the application programmer. It is not intended for DB2 Server for VSE use. See the IBM Language Environment for VSE/ESA Programming Guide for more details.